I loved the visual/industrial design of Oblivion but I'm not really sure what to search for to find more. Is there a name for this sleek, clean, "optimistic" sci-fi style? Do you know who some talented artists with this style are?
Closest I can think of is Simon Stålenhag but he's more grungy and suburban.
well the 3d artist for oblivion was Daniel Simon so check his other works.
Neville Page (Tron Legacy Stuff)
Steven Messing (Prometheus)
and maybe check out some works from Zaha Hadid Architects and AADRL.